Miniature switch



Nov. 26, 1957 H. A. MILLER, SR

MINIATURE SWITCH dMy23 956 FIG.2.

H. A. MILLERLSR.

A'ITORN 5 7 nited States The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

The present invention relates to switches and more particularly to a new and improved plunger type switch. Moreover, the present invention contemplates the provision of a new and improved quick .cl'osing miniature switch which is normally and adjustably biased into a closed position and which is Well suited for use in high speed test equipment for interrupting an electrical control circuit therefor or for interrupting an electrical circuit such, for example, as an emergency or normal means for stopping an electrically driven machine or the like. The device of the present invention comprises a spring actuated plunger slidably and rotatably arranged within a suitable casing and having an adjustable collar or contact carried thereby normally in engagement with an annular complementary contact member mounted in the casing, the plunger being provided with an actuating knob whereby the plunger may be moved at will an amount sufficient to cause disengagement of the contact from the annular contact. The collar is threadedly mounted on the plunger and may be adjusted by rotating the knob thereby to compress the spring and vary the closing cycle of the switch.

An object of the present invention is to provide a new and improved plunger type switch.

Another object of the invention is the provision of a normally closed isolating switch having new and improved contact means for interrupting an electric circuit.

Still another object of the invention is the provision of a normally closed switch adapted to break an electric circuit as the switch is actuated to an open position and having new and improved means for varying the time interval at which the movable switch contact when moved from an open position is restored to a closed position.

A still further object of the invention is the provision of a spring biased plunger switch having new and improved means for varying the closing cycle of the switch after the switch has been actuated from a normally closed position to an open position.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawing wherein:

Fig. l is an enlarged longitudinal sectional view of the switch constructed in accordance with the present invention;

Fig. 2 is a cross sectional view taken on the line 2-2 of Fig. 1; and

Fig. 3 is a view in perspective of the annular contact mem ber removed from the switch casing.

Referring now to the drawing for a more complete understanding of the invention and more particularly to Fig. 1 thereof, the reference character generally indicates esmfofiis 2 a switch constructed in accordance with the present invention. The switch comprises -a casing 11 composed of any material suitable for the purpose and having a cylindr'ical body 12' and an annular flange 13 formed on and extending outwardly from one end thereof. A well or recess 14 is formed in the other end of the body in com munication with a bore 15' of reduced diameter with respect to the well, the bore extending through the flange 13.

A retainer or support indicated by the numeral 16 and composed of any suitable insulating material is threaded into the well 14 as at 17 and comprises a tubular extension 18 having a groove 19 formed therein, the purpose of which will be more clearly apparent as the description proceeds.

Disposed within the casing 11 and generally indicated by the reference character 21 is a fixed contact member comprising a circular member 22 having an annular contact element 23 and a terminal 24 formed thereon. The terminal is disposed at a right angle with respect to the member 22 and disposed within a recess 26 formed in the casing 11, the recess 26 terminating in a shallow recess 27 for receiving the terminal 24. 'It will be noted in Fig. 1 that the contact member 21 is clamped between a shoulder 28 formed on the casing 11 and the terminal end of the tubular extension 18.

An actuating plunger generally indicated by the reference character 29 is m'o va'bly arranged within the casing 11 and comprises a shaft or rod 31 threaded as at 3233 for threaded engagement with an actuating knob 30 and a movable contact or collar 34 respectively. The contact 34 carries a pin 35, the free end of the pin being disposed wit'hin the groove or slot 19 thereby to permit sliding movement of the contact 35 as the shaft 31 is rotated by knob 30. It will be understood that the aforesaid contact member 21, shaft 31 and contact 34 are composed of any suitable highly conductive material such, for example, as beryllium copper or the like.

The contact 34 is normally maintained in engagement with the annular contact member 23 by a spring 36 arranged about the shaft 31 and having one end in engagement with a shoulder 37 formed on contact 34, the other end thereof being in engagement with a Wall 38 formed on the support 16. The wall 38 is provided with an opening 39 throuugh which the shaft 31 extends thereby to permit sliding and rotative movement of the plunger.

From the foregoing, it will be understood that upon rotation of the plunger by the knob 30, the contact 34 in threaded engagement with shaft 31 thereof, will be moved slidably within the casing by reason of the pin 35 and slot 19 and thus the spring 36 may be compressed a desired amount thereby increasing the impelling force of the spring. Thus by this arrangement it will be apparent that the closing cycle of the switch may be varied, if desired, by the aforesaid adjustable contact structure.

Conductors 41 and 42 are connected to the terminal 31 and shaft 24 respectively as at 43 and 44 to provide an external electrical connection to the switch.

In accordance with the present invention a new and improved normally closed quick acting miniature switch has been devised for breaking an electric circuit as the switch is actuated. to an open position and having novel means for varying the time interval at which the movable switch contact is moved from an open position to a closed position.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claim the invention may be practiced otherwise than as specifically described.

What is claimed as new and desired to be secured Letters Patent of the United States is:

In a miniature switch, a cylindrical casing, a plunger tby Patented Nov. 26, 1957 3 slidably and rotatably disposed within the casing, an adjustable contact collar threaded on said plunger, a complementary annular contact member secured within the casing and normally engaged with said contact collar, a spring disposed about said plunger in engagement with said contact collar and the casing for maintaining the contact knob on one end of the plunger for disengaging the contact collar from said annular contact member as the knob is depressed and the plunger is moved slidably thereby, said contact collar being moved slida-bly to compress said spring as the plunger is rotated by said knob 4 whereby the time of operation of the switch may be varied, a slot formed within said casing, and means carried by the contact collar and disposed within said slot for causing the collar to be moved slidably as the plunger is rotated.

References Cited in the file of this patent UNITED STATES PATENTS 

